Instantaneous leg length discrepancy determination by "thigh-leg" technique.
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Biometry↗
Biomedical subjects
C F Smith
Publications and source records attributed to C F Smith.
Arthroscopic shoulder surgery with three different laser systems: an evaluation of laser applications.
Twelve cadaveric shoulder arthroscopies were performed to evaluate the use of lasers as an adjunctive tool in arthroscopic shoulder surgery. The three most common lasers historically used in orthopedic surgery were examined: Holmium:YAG, Neodymium:YAG, and the CO2. The following parameters were evaluated for each laser system: (1) ease of use of the laser system and handpiece; (2) ability to excise and trim bursae, synovium, ligament, tendon, bone, and articular cartilage; and (3) ability to contract ligaments and capsule by heat transfer. None of these lasers efficiently cut bone, whereas all three systems readily debrided the soft tissues around the shoulder. The free-beam Ho:YAG and CO2 systems heat contracted soft tissues with more control than the contact Nd:YAG. The fiberoptic delivery system of the Neodymium:YAG and Holmium:YAG laser performed well in the saline arthroscopy, and the CO2 delivery system was cumbersome. Overall, the CO2 system removed tissue better than the others, but its difficult use favored the Holmium laser as the best overall current laser system for shoulder arthroscopy.
Aluminum Silicates↗
In vitro analysis of laser meniscectomy.
Partial meniscectomies were performed on 32 fresh human meniscal autopsy specimens. The following laser systems were tested: carbon dioxide (CO2), neodymium:yttrium aluminum garnet (Nd:YAG), potassium titanyl phosphate (KTP), holmium:YAG (Ho:YAG), and excimer. Meniscectomies with these lasers were compared with scalpel, mechanical, and electrocautery meniscectomies. Lasers were applied to specimens in and out of normal saline. Routine hematoxylin and eosin and sirius red sections were prepared for each specimen, and the depths of thermal changes were analyzed. Scanning electron microscopy was used to visualize the meniscectomy interface. Among these specimens, the scalpel and mechanical meniscectomies showed the least extension of cellular changes (range, 10-15 nm). The excimer laser caused the least tissue changes of the lasers tested. Tissue changes were less extensive with the pulsed CO2 laser than with the holmium:YAG, neodymium:YAG, and KTP lasers. Scanning electron microscopy showed that use of the scalpel meniscectomy resulted in the smoothest meniscectomy edge, followed by use of the excimer, CO2, holmium:YAG, neodymium:YAG, and KTP lasers. The most surface disruption occurred with electrocautery. Meniscectomies under saline required more energy and took longer in each case, with the holmium:YAG, neodymium:YAG, and CO2 laser cutting the best. Saline meniscectomies showed less thermal change. The CO2 and KTP lasers cut best in air.
Adult↗
A spectrophotometer analysis of light absorption in the human meniscus.
The spectrophotometer analysis of light absorption curves in human meniscal tissue showed a reproducible series of graphs for varying tissue thickness, age, zone, and sectioning plane. These data show water as the essential reason for light absorption in the infrared portion of the light spectrum. The excimer laser in the ultraviolet region, and wavelengths around 2000 nm in the infrared region, appeared to provide the best wavelength match for laser energy transfer and the cutting or ablating of meniscal tissue. On-going research into clinical applications should focus on these wavelengths.
Absorption↗
The biological effects of carbon dioxide laser surgery on rabbit articular cartilage.
A pulsed carbon dioxide laser made predetermined superficial and deep (subchondral) lesions through arthrotomies on the femoral condyles of adult New Zealand rabbits. Twenty rabbits, including controls, were divided into acute, 1-, 3-, 6-, and 12-month sacrifice groups. Early sacrifice groups showed some fibrous ingrowth from the deep lesions, but not the superficial lesions, and this was not seen in the 6- or 12-month groups. Cells below and adjacent to the laser lesions appeared viable when compared with controls. In each group studied, no histologic evidence of healing or fibrous covering in the superficial or deep laser lesions was found. No adverse clinical effects (synovitis, infection) were found in the laser groups, and the laser permitted excellent depth control during vaporization. However, the authors caution against irradiating articular cartilage.
Animals↗
The effects of the neodymium laser on meniscal repair in the avascular zone of the meniscus.
Thirty mature New Zealand white rabbits were divided into four surgical groups, and a 3- to 4-mm incision was made in the inner avascular zone of the central third of the medial meniscus. In group I, the tear was not treated by lasering or suturing. In group II, the tear was sutured. Group III was given four different doses of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation with no suturing. Group IV underwent meniscal suturing followed by the same four different laser irradiation doses. The animals were killed at 2, 4, and 6 weeks, with gross and histologic evaluation of the healing responses by group and time. The overall results showed no healing of this meniscal tear in the avascular zone. Suturing generally showed increased cellular infiltration. The varying doses of the Nd:YAG lasing demonstrated no gradient effect, and no "welding" of menisci was noted. The maximum cellular inflammatory response was noted in the sutured and lased menisci, reinforcing the importance of a stable meniscal environment for healing meniscal tears.
Animals↗
Communicable hysteria?
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Acquired Immunodeficiency Syndrome↗
Lasers in orthopedic surgery.
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Arthroscopy↗
Synthesis and structure-activity relationships of some 6 beta-acrylamido penicillins.
Syntheses are described for penicillins (4b approximately 4i, 5a and 5b) which possess a 6 beta-(2-heteroaryl-3-substituted)-propenamido side-chain of fixed geometry. In vitro results for these compounds against a range of Gram-positive and Gram-negative bacteria showed in most cases good stability against both penicillinase and TEM-1 beta-lactamase; analogues (4b approximately 4i) bearing a 2-(2-aminothiazol-4-yl) unit showed the best intrinsic activity, the cyclohexyl compound (4b) being the most promising. The 1-acetoxyethyl ester (6) of 4b was also prepared; in experimental animal studies the in vivo properties of this compound compared favourably with cefuroxime axetil and are reported together with selected in vivo data for the other compounds.
Animals↗
Recent advances in electrical stimulation.
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Animals↗
Selectivity profile of the alpha 2-adrenoceptor antagonist efaroxan in relation to plasma glucose and insulin levels in the rat.
The effects of efaroxan (RX 821037A; 2-[2-(2-ethyl-2,3-dihydrobenzofuranyl)]-2-imidazoline HCl) at alpha 1- and alpha 2-adrenoceptors were investigated in isolated tissues, pithed rats and conscious rats. In isolated tissues, efaroxan competitively antagonised the inhibitory effects of p-aminoclonidine in the electrically stimulated (0.1 Hz) rat vas deferens, (pA2 = 8.89) and the contractile effects of phenylephrine on the rat anococcygeus muscle (pA2 = 6.03). Efaroxan had a selectivity ratio (alpha 2/alpha 1) of 724 compared to a value of 182 for idazoxan. In pithed rats, the i.v. doses of efaroxan (mumol/kg) producing 2-fold shifts in dose-response curves for UK-14,304 at prejunctional cardiac alpha 2-adrenoceptors and postjunctional vascular alpha 2-adrenoceptors, and for cirazoline at postjunctional vascular alpha 1-adrenoceptors, were 0.05, 0.13 and 2.96, respectively. In conscious fasted rats, prazosin (5 mg/kg p.o.) increased resting glucose levels and exacerbated the hyperglycaemic effects of UK-14,304 and adrenaline. In contrast, efaroxan (1-5 mg/kg p.o.) had little effect on resting plasma glucose but markedly antagonised the hyperglycaemic actions of UK-14,304 and adrenaline. Efaroxan increased resting plasma insulin levels and markedly potentiated the rise in insulin levels produced by adrenaline; this latter effect was prevented by the co-administration of propranolol. These results demonstrate that efaroxan is a potent and selective alpha 2-adrenoceptor antagonist and provide further support for the involvement of alpha 2-adrenoceptors in glucose homeostasis.
Adrenergic alpha-Antagonists↗
Investigations on the "set-point" theory of benzodiazepine receptor function.
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Animals↗
Synthesis and biological evaluation of 14-alkoxymorphinans, V: 6-Deoxyocyprodime, an opioid antagonist with decreased mu receptor selectivity in comparison to cyprodime.
N-Cyclopropylmethyl-4,14-dimethoxymorphinan (4) and N-cyclopropylmethyl-4-hydroxy-14-methoxymorphinan (5) have been prepared from cyprodime (1) by Wolff-Kishner reduction. Pharmacological studies (mouse vas deferens and guinea pig ileum preparations) revealed that there was no significant decrease of 4 in antagonist activity but in mu selectivity when compared with 1. The phenol 5 showed partial agonism at mu, kappa and delta receptors.
Animals↗
Lasers in orthopaedic surgery.
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Forecasting↗
(-)-N,N'-but-2-ene-1,4-diylbimorphinans.
N,N'-But-2-ene-1,4-diylbimorphinans 1-3 have been synthesized and pharmacologically evaluated. Bimorphinans 1 and 3 show opioid antagonist activity and preference for mu and kappa opioid receptors in mouse vas deferens and guinea pig ileum preparations.
Animals↗
The effect of total-body irradiation on corneal neovascularization in the Fischer 344 rat after chemical cauterization.
Previous investigations of corneal neovascularization after irradiation yielded discordant results. Most studies indicated that new blood vessel formation in the cornea is inhibited by irradiation. However, others reported that angiogenesis after corneal cauterization is similar in both irradiated and nonirradiated animals. To assess the effect of total-body irradiation on neovascularization further, the amount of angiogenesis was determined in irradiated rats after chemically induced corneal injury. Corneal tissue was evaluated quantitatively with computerized image analysis 2, 3, or 4 days postcautery in rats perfused with India ink and gelatin immediately after death. The rats were exposed to a single dose (9 Gy) of total-body irradiation 6 days before corneal cauterization. In both the nonirradiated and irradiated rats, neovascularization increased with the duration of the postcautery interval. The amount of corneal neovascularization was not significantly different in the irradiated and nonirradiated rats at any of the postcautery intervals studied. This investigation suggests that endothelial cell migration plays a more important role than cell replication in the pathogenesis of corneal angiogenesis in the Fischer 344 rat. Moreover, the suppression of corneal angiogenesis by irradiation may be dependent on the experimental conditions and species examined.
Animals↗
Proteoglycan biosynthesis by human corneas from patients with types 1 and 2 macular corneal dystrophy.
Corneal buttons were obtained from patients with types 1 and 2 macular corneal dystrophy (MCD) and from control patients with Fuchs' dystrophy or keratoconus. Buttons were incubated for 20 h in the presence of [3H]glucosamine or [2-3H]mannose. Radiolabeled proteoglycans and lactosaminoglycan-glycoproteins (L-GPs) were purified using chromatography on Q-Sepharose, Superose 6, and octyl-Sepharose. They were identified using chondroitinase ABC, keratanase or endo-beta-galactosidase digestion, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis or Superose 6 chromatography. This study confirms previous reports that type 1 MCD corneas synthesize a normal dermatan sulfate-proteoglycan (DS-PG) and an abnormal keratan sulfate-proteoglycan (KS-PG). The data indicate that typ 1 MCD corneas synthesize L-GP instead of KS-PG. This L-GP has a core protein of similar hydrophobicity (elution from octyl-Sepharose) and nearly similar mass (42 kDa) as the core protein of the KS-PG. It has identical glycoconjugates as those of the KS-PG except that they lack sulfate. Thus, type 1 MCD fails to synthesize keratan sulfate as a result of a defect in a sulfotransferase specific for sulfating lactosaminoglycans. Further, proteoglycans synthesized by a cornea from a patient with type 2 MCD were studied. This cornea synthesized a normal ratio of KS-PG to DS-PG although net synthesis of proteoglycans was approximately 30% below normal. The KS-PG appeared normal whereas the DS-PG had dermatan sulfate chains that were approximately 40% shorter than normal.
Cells, Cultured↗
Synthesis and biological evaluation of 14-alkoxymorphinans. 3. Extensive study on cyprodime-related compounds.
A series of cyprodime-related compounds (2, 4-12, and 26) has been synthesized and evaluated for opioid agonist and antagonist activity with the mouse vas deferens and guinea pig ileum preparations. None of the changes to cyprodime, including the introduction of a 3-OMe group, increasing and decreasing the size of or completely removing the substituent in position 4, replacing the N-cyclopropylmethyl group with an N-allyl group, or replacing the 14-OMe with an 14-OEt substituent, resulted in an improved mu antagonist profile and most were detrimental either in terms of mu selectivity and potency or increased agonist activity. Increasing the length of the substituent in position 4 resulted in a compound (6a) with a very similar profile to that of cyprodime.
Animals↗